DEHYDROBENZENE IN THE REACTION OF A TANDEM [4+2]/[4+2] CYCLOADDITION WITH LINEAR BIS-FURYLDIENES
DOI:
https://doi.org/10.1007/6364Keywords:
aryne, dehydrobenzene, 1, 4, 5, 8-diepoxynaphthalenes, furan, 7-oxabicyclo[2.2.1]heptane, IMDAF reaction, intramolecular Diels–Alder reaction, tandem [4 2]/[4 2] cycloaddition.Abstract
Tandem [4+2]/[4+2] cycloaddition between bis-dienes containing two furan rings and dehydrobenzene as a dienophile was studied. It was shown that dehydrobenzene generated in situ from 2-(trimethylsilyl)phenyl trifluoromethanesulfonate is capable of a facile intermolecular [4+2] cycloaddition to a furan moiety of a diene at room temperature. The next step, that involves intramolecular Diels–Alder reaction (the IMDAF reaction) with the second furan ring, requires elevated temperature up to 80°С. It has been shown that even under optimal conditions the yields of the target annulated 1,4:5,8-diepoxynaphthalenes do not exceed 50%. The main byproducts are double cycloaddition adducts formed during the interaction of two aryne subunits with both furan rings of the initial bis-diene.